Attached to the Email Message of 10/25/01 from Sam Mehta

Attached to the Email Message of 10/25/01 from Sam Mehta

Comments on the Tentative Order for WQCP

October 25, 2001

Page 1

ATTACHED TO THE EMAIL MESSAGE OF 10/25/01 FROM SAM MEHTA

Comments on the Tentative Order and Tentative Self-Monitoring Program for City and County of San Francisco, San Francisco International Airport, Water Quality Control Plant, San Mateo County (NPDES Permit Reissuance)

The following are the San Francisco International Airport’s comments on the Tentative Order for the Airport’s Water Quality Control Plant.

  1. Fact Sheet Items 4-a-1. Delete the words “ except for the addition of CBOD limits” from the third sentence. The existing permit contains similar CBOD limits.
  1. Fact Sheet Items 4-a-3. Delete the last sentence that reads as follows:” The CBOD parameter and associated limits were not included in the existing permit, but have been included in the draft permit at the request of the discharger.”
  1. Finding 2 WQCP Flow Rates. The average dry weather flow for May through September for the last three years was 0.88 mgd. Based on these flow rates we believe that the average dry weather flow at the WQCP is still below 1 mgd.
  1. Finding 5. Based on the above comment we request that the WQCP be classified as a minor discharge.
  1. Finding 8. Please modify the first sentence in this finding to read as follows “ Sludge from the Water Quality Control Plant is stabilized through anaerobic digestion and then pumped to sludge drying beds or transported to another permitted wastewater treatment facility owned and operated by the Discharger for further treatment and final disposal.”
  1. Finding 11. Due to the serious nature of Discharger’s current fiscal situation, all Airport budget items, including long planned capital improvement projects, are under review to determine if, how and when such items may be funded. It is therefore impossible to state specifically at this time how the Airport will achieve the necessary modifications to the WQCP to ensure adequate redundancy. Accordingly we request that the second paragraph in

this finding be modified to read as follows: ”During the next three years the Discharger will be modifying the existing treatment plant to provide more redundancy.”

  1. Finding 43. The City and County objects to the imposition of an effluent limit for 4,4-DDE and dieldrin because, as the RWQCB acknowledges, neither of these compounds have been detected in the WQCP’s effluent. The proposed WQBELs for dieldrin and 4,4-DDE are several orders of magnitude lower than the current analytical method detection limits for these compounds. Therefore, it would be infeasible to meet the proposed WQBELs for dieldrin and 4,4-DDE in the WQCP effluent.

Also, even though the order allows dieldrin and 4,4-DDE concentrations in the effluent up to their respective Minimum Level (0.01 g/L for dieldrin and 0.05 g/L for 4,4-DDE), the Airport would be unable to meet the proposed limits for dieldrin and 4,4-DDE on a consistent basis. The Airport demonstrated this situation in the Feasibiliy Study submitted to the Board on September 4, 2001. On page 2 of Table 4 of the Feasibility Study it is shown that for 27 sampling events over the three year period from 1997 through March 2000 dieldrin was reported on 12 separate occasions at analytical method detection limits that were above 0.01 g/L and 4,4-DDE was reported on 5 separate occasions at analytical method detection limits that were above 0.05 g/L. Therefore the City and County requests that interim effluent limits be established for dieldrin and 4,4-DDE that could be met under current WQCP performance conditions and for generally available analytical methodologies.

  1. Finding 62. The City and County objects to the imposition of “performance-based” interim effluent limitations for mercury that are, in fact, based on pooled data gathered from other dischargers. Section 2.1 of the State Implementation Plan (SIP) requires interim limits to reflect “current treatment facility performance or existing permit limitations, whichever is more stringent.” Interim average monthly effluent limitations for mercury for the WQCP should therefore be based on the lower of: i) the past three years of actual performance (0.39 g/L) or ii) the limit set in the existing permit (0.21 g/L), which would result in an average monthly effluent limitation of 0.21 g/L.
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